Add function to get all HUD elements (#14042)

doc/client_lua_api.md

@@ -779,6 +779,10 @@ Methods:
     * See [`HUD definition`](#hud-definition-hud_add-hud_get)
 * `hud_get(id)`
     * returns the [`definition`](#hud-definition-hud_add-hud_get) of the HUD with that ID number or `nil`, if non-existent.
+* `hud_get_all()`:
+    * Returns a table in the form `{ [id] = HUD definition, [id] = ... }`.
+    * A mod should keep track of its introduced IDs and only use this to access foreign elements.
+    * It is discouraged to change foreign HUD elements.
 * `hud_remove(id)`
     * remove the HUD element of the specified id, returns `true` on success
 * `hud_change(id, stat, value)`

doc/lua_api.md

@@ -7803,6 +7803,10 @@ child will follow movement and rotation of that bone.
     * `stat` supports the same keys as in the hud definition table except for
       `"type"` (or the deprecated `"hud_elem_type"`).
 * `hud_get(id)`: gets the HUD element definition structure of the specified ID
+* `hud_get_all()`:
+    * Returns a table in the form `{ [id] = HUD definition, [id] = ... }`.
+    * A mod should keep track of its introduced IDs and only use this to access foreign elements.
+    * It is discouraged to change foreign HUD elements.
 * `hud_set_flags(flags)`: sets specified HUD flags of player.
     * `flags`: A table with the following fields set to boolean values
         * `hotbar`

games/devtest/mods/testhud/init.lua

@@ -210,3 +210,23 @@ minetest.register_on_leaveplayer(function(player)
 	player_font_huds[player:get_player_name()] = nil
 	player_waypoints[player:get_player_name()] = nil
 end)
+
+minetest.register_chatcommand("hudprint", {
+	description = "Writes all used Lua HUD elements into chat.",
+	func = function(name, params)
+		local player = minetest.get_player_by_name(name)
+		if not player then
+			return false, "No player."
+		end
+
+		local s = "HUD elements:"
+		for k, elem in pairs(player:hud_get_all()) do
+			local ename = dump(elem.name)
+			local etype = dump(elem.type)
+			local epos = "{x="..elem.position.x..", y="..elem.position.y.."}"
+			s = s.."\n["..k.."]  type = "..etype.." | name = "..ename.." | pos = ".. epos
+		end
+
+		return true, s
+	end
+})

src/player.cpp

@@ -139,6 +139,12 @@ HudElement* Player::getHud(u32 id)
 	return NULL;
 }
 
+void Player::hudApply(std::function<void(const std::vector<HudElement*>&)> f)
+{
+	MutexAutoLock lock(m_mutex);
+	f(hud);
+}
+
 HudElement* Player::removeHud(u32 id)
 {
 	MutexAutoLock lock(m_mutex);

src/player.h

@@ -26,6 +26,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/basic_macros.h"
 #include <list>
 #include <mutex>
+#include <functional>
 
 #define PLAYERNAME_SIZE 20
 
@@ -225,6 +226,7 @@ class Player
 	}
 
 	HudElement* getHud(u32 id);
+	void        hudApply(std::function<void(const std::vector<HudElement*>&)> f);
 	u32         addHud(HudElement* hud);
 	HudElement* removeHud(u32 id);
 	void        clearHud();

src/script/lua_api/l_localplayer.cpp

@@ -422,6 +422,26 @@ int LuaLocalPlayer::l_hud_get(lua_State *L)
 	return 1;
 }
 
+// hud_get_all(self)
+int LuaLocalPlayer::l_hud_get_all(lua_State *L)
+{
+	LocalPlayer *player = getobject(L, 1);
+	if (player == nullptr)
+		return 0;
+
+	lua_newtable(L);
+	player->hudApply([&](const std::vector<HudElement*>& hud) {
+		for (std::size_t id = 0; id < hud.size(); ++id) {
+			HudElement *elem = hud[id];
+			if (elem != nullptr) {
+				push_hud_element(L, elem);
+				lua_rawseti(L, -2, id);
+			}
+		}
+	});
+	return 1;
+}
+
 LocalPlayer *LuaLocalPlayer::getobject(LuaLocalPlayer *ref)
 {
 	return ref->m_localplayer;
@@ -483,6 +503,7 @@ const luaL_Reg LuaLocalPlayer::methods[] = {
 		luamethod(LuaLocalPlayer, hud_remove),
 		luamethod(LuaLocalPlayer, hud_change),
 		luamethod(LuaLocalPlayer, hud_get),
+		luamethod(LuaLocalPlayer, hud_get_all),
 
 		luamethod(LuaLocalPlayer, get_move_resistance),
 

src/script/lua_api/l_localplayer.h

@@ -93,6 +93,8 @@ class LuaLocalPlayer : public ModApiBase
 	static int l_hud_change(lua_State *L);
 	// hud_get(self, id)
 	static int l_hud_get(lua_State *L);
+	// hud_get_all(self)
+	static int l_hud_get_all(lua_State *L);
 
 	static int l_get_move_resistance(lua_State *L);
 

src/script/lua_api/l_object.cpp

@@ -1743,6 +1743,28 @@ int ObjectRef::l_hud_get(lua_State *L)
 	return 1;
 }
 
+// hud_get_all(self)
+int ObjectRef::l_hud_get_all(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	ObjectRef *ref = checkObject<ObjectRef>(L, 1);
+	RemotePlayer *player = getplayer(ref);
+	if (player == nullptr)
+		return 0;
+
+	lua_newtable(L);
+	player->hudApply([&](const std::vector<HudElement*>& hud) {
+		for (std::size_t id = 0; id < hud.size(); ++id) {
+			HudElement *elem = hud[id];
+			if (elem != nullptr) {
+				push_hud_element(L, elem);
+				lua_rawseti(L, -2, id);
+			}
+		}
+	});
+	return 1;
+}
+
 // hud_set_flags(self, flags)
 int ObjectRef::l_hud_set_flags(lua_State *L)
 {
@@ -2691,6 +2713,7 @@ luaL_Reg ObjectRef::methods[] = {
 	luamethod(ObjectRef, hud_remove),
 	luamethod(ObjectRef, hud_change),
 	luamethod(ObjectRef, hud_get),
+	luamethod(ObjectRef, hud_get_all),
 	luamethod(ObjectRef, hud_set_flags),
 	luamethod(ObjectRef, hud_get_flags),
 	luamethod(ObjectRef, hud_set_hotbar_itemcount),

src/script/lua_api/l_object.h

@@ -300,6 +300,9 @@ class ObjectRef : public ModApiBase {
 	// hud_get(self, id)
 	static int l_hud_get(lua_State *L);
 
+	// hud_get_all(self)
+	static int l_hud_get_all(lua_State *L);
+
 	// hud_set_flags(self, flags)
 	static int l_hud_set_flags(lua_State *L);